The ultimate goal of this research is to protect health-care and corrections workers from occupational exposure to Mycobacterium tuberculosis by defining the performance of respiratory protection with respect to mycobacterium aerosols. The specific aims are: 1) to determine the density of the droplet nuclei that result from the aerosolization of solutions containing Mycobacterium tuberculosis; 2) to determine the particle size distribution and particle shapes characteristic of the aerosol generated by the cough of humans infectious with tuberculosis; 3) to explore a new bioaerosol analytical technique that incorporates the new firefly luciferase assay for mycobacterium; 4) to determine the leak characteristics of respiratory protection with respect to mycobacterium aerosols and using a method that incorporates inhalation and exhalation into the respirator performance test; and 5) to determine what, if any, differences in respirator performance result when respirators are challenged with a standard aerosol (i.e. NaCI, dioctyl phthalate (DOP)) and M. tuberculosis aerosols. Adequately characterized respirator function will assist the government, employers, and researchers in developing protective, useable, and cost effective respiratory protection programs for protection against tuberculosis. This will reduce the risk of tuberculosis infection associated with work in these areas. Novel applications will be used in the study, such as: density gradient centrifugation for determination of tuberculosis droplet nuclei density; the firefly luciferase assay will be adapted for use in air sampling for bioaerosols; and respirators will be challenged using tuberculosis aerosols, dioctyl phthalate, and NaCI aerosols. The respirator tests will incorporate the facepiece leakage inherent in current particulate respirator design.